Multi-speed fluid translator



D- 10, 1968 G. STEIN ErAL.v

MULTI-SPEED FLUID TRANSLATOR 2 Sheets-Sheet z Filed D60. 8. 1966 l I l l vE/vroRs GARY STE/N AIN LARRY E HALWAS A77'. RWE-75,

United States Patent O 3,415,160 MULTI-SPEED FLUID TRANSLATOR Gary Stein, Brookfield, and Larry E. Halwas, Pewaukee, Wis., assignors to Applied Power Industries, Inc., Menomonee Falls, Wis., a corporation of Wisconsin Filed Dec. 8, 1966, Ser. No. 600,159 4 Claims. (Cl. 91-6) ABSTRACT OF THE DISCLOSURE A fluid motor having an end plate in which a valving system is housed with an operating handle rotatably secured in the end plate and connected to the valve for changing the fluid intake capacity of the motor in either direction.

This invention relates to a fluid translator and more particularly relates to a translator of the hydraulic motor type having multi-speed capability controllable by lever means mounted on the motor housing.

Multi-speed motors are known to the prior art. Heretofore, however, speed control systems have encompassed relatively complicated and expensive motor designs usually of the pivoting swash plate type or in the alternative, those having constant displacement pumps with separate valving mechanisms. The primary objective of this invention is to provide a motor of the axial piston type in which a valve assembly encloses one end thereof and in which the assembly provides the portings and control mechanism necessary to the speed-change capability.

Another objective of this invention is to provide a fluid motor assembly which has the capacity of different speed ranges in each direction and said ranges being selectable 4by a single operating handle mounted on the motor assembly.

These and other important objectives and adv-antages of the invention will hereinafter become more fully apparent from the following description of the drawings, illustrating a presently preferred embodiment thereof, and wherein:

FIGURE l is a cross section of a translator housing taken along the line 1-1 0f FIGURE 2;

FIGURE 1a is a cross section of the spool valve of FIGURE l shown in a different position;

FIGURE 2 is -a cross-sectional View along the line 2-2 of FIGURE 1;

FIGURE 3 is a cross-sectional view taken along the line 3 3 of FIGURE l; and

FIGURE 4 is a schematic view of a hydraulic drive system in which the instant invention is used.

Referring now to the drawings wherein like elements are indicated by like numerals, the numeral refers to translator housing. An end cap 12 encloses one end of said housing and is secured thereto by a plurality of circumferentially spaced bolts 14. An output shaft 16 is rotatably received within the translator at two axially spaced locations by anti-friction bearings 18 and 20. A cylinder barrel 22 is fixedly secured to the shaft 16 for rotation therewith. The barrel is formed with a plurality of circumferentially spaced and axially positioned chambers or cylinders 24 in each of which a hollow piston 26 is adapted to reciprocate. At the end of each chamber, an opening 2S is provided which leads to the forward planar end 27 of the barrel. A stationary cam plate 28 is fixed to the interior of the translator by cap bolts 29 and presents an inclined surface 30 to pistons 26. Each of the pistons terminate at their rearward end in spherical heads 29'on which tiltable slippers 32 are received. The slippers 32 slide against the inclined surface 30, and as the cylinder barrel is rotated, the pistons reciprocate in a manner well known to the art.

The other end of housing 10 is enclosed by a valve block or assembly 34 secured to the housing by a plurality of cap bolts 36. The block 34 has a smoothly finished interior planar surface which is juxtaposed in face-to-face relationship with the planar end 27 of the barrel.

The block 34 is provided along its surface 40 with a plurality of kidney-shaped slots 42, 44, 46 and 48 which are disposed radially to alternately come in contact with each of the passageways 25 as the barrel 22 rotates. Note that the section of FIGURE 1 is taken through one set of grooves 42 and 44 which act as intake chambers when the motor is driven in a first direction. When the motor is working in this first direction, the other pair of slots 46 and 48 are working as exhausts. The reverse is true, of course, when the pump is driven in the opposite direction. This will become more obvious hereinafter.

The valve block is formed with a pair of ports 50 and 50 which are connected to a hydraulic system. The direction in which the barrel 22 is driven is determined by in which of the ports 50 or 50 the pressurized fluid is received. For purposes of proceeding with the description it will be first assumed that pressurized uid is received by the port 50 and exhausted through port 50'. Initially the slots 42 and 44 will be referred to as intake slots and slots 46 and 48 as exhaust slots.

The intake port 50 is communicated with the intake slot 42 by way of a cross-bore 52 and the port 50 is communicated with slot 44 by Way of a cross-bore 53. As shown in both FIGURES 1 and 2, fluid in intake 50 can be blocked from reaching the slot 44 by way of a pool 54 which is disposed across passageway 53.

The spool 54 is rotatably mounted in assembly 34 by the bearings 55 and 56 at either end of the transverse bore 57. A manual operating handle 58 is affixed to the spool exteriorly of the assembly. The spool is generally cylindrical but is grooved at 60 and 62 on one side of a midsection 61 and is grooved at 60 and 62 on the other side thereof. The handle 58 rotates the spool to two principal positions; namely, to a first position as shown in FIGURE 1 wherein the peripheral surface of the spool blocks conduit 53 and to a second position as shown in FIGURE 2 wherein groove 60 opens the fluid path along passageway 53. The intake port 50 and the depression 64 formed in the assembly, are communicated by the bore 65. This permits the pressure in intake 50 to be reflected at the opposite side of the spool to depression 64 to thus set up a counterbalance which eliminates spool binding at high pressures.

Outwardly from the grooves 60, 62, 60 and 62' the spool is reduced in diameter at and 70 to thereby form annular chambers with bore 51. Transverse bores 72 and 72 are respectively drilled through these reduced portions. The bore 72 intersects a longitudinal bore 74 formed in one end of the spool and the bore 72 intersects a longitudinal bore 74 formed at the other end thereof. The bores 74 and 74 are communicated to tank via the annular collecting grooves 77 and 77' and the cross bore 79 and 79. One-way checks 76 and 76' are disposed intermediate the lengths of bores 74 and 74. These checks are in the nature of relief valves and protect the motor if unwanted pressure build-ups occur.

In order to prevent cavitation, the block is provided with the prefill inlet checks 84 and 86. The prefill passageway are communicated with the power source via their bores and, as best understood by reference tothe schematic of FIGURE 4, midway therebetween are communicated to tank via the passageway 80. In the event cavitation conditions are presented, iluid will be drawn through the check 84 and 86 and the condition will be relieved.

Assuming, for purposes of description, that barrel 22 is rotating clockwise as it faces the speed adjusting assembly in FIGURE 3, and that the line 90 (FIGURE 4) from the power source is providing pressurized iluid to intake 50, it can be seen that the arcuate recesses 42 and 44 are subjected to pressurized iluid respectively via lines 52 and 53 when spool 54 is in the position of FIGURE 1a. Assume further, that the portion to the right of the vertical centerline 84 of FIGURE 3 extends from point of maximum thickness on cam plate 28 to a lower point of minimum thickness, it can be seen that fluid will be supplied to slots 42 and 44 through their entire power strokes from the vertical highs to their vertical lows. As the pistons continue their travel and traverse the arcuate slots 46 and 48 they will exhaust fluid to tank via spool bore 53 and groove 60' as well as spool bore 52'. In this instance since the pistons are receiving the pressurized fluid through their entire power stroke, the motor will run at maximum horsepower (displacement) and minimum speed.

Assuming identical conditions, but with spool valve 54 in its blocking (FIGURE 1) position, the slot 44 is not pressurized and therefore the pistons 26 will not receive pressurized fluid as they traverse that recess. Since the pistons receive pressurized fluid only as they traverse slot 42 decreased displacement, but greater speed results. Essentially, the reduced displacement is accomplished by applying uid under pressure to each piston for only a portion of its power stroke.

For all practical purposes a vertical mid-plane through the valve assembly as it is disposed in FIGURE 2 divides it into two halves of mirror image. As can be noted from the drawings, the elements to the left of such an imaginary `line are indicated by the same arabic numerals with prime marks. It should be understood that the reverse of the above operation results if the pressurized fluid from a pressure source is applied to bore 50 as the intake bore. Thus, there has been described a motor having a step variable capability in either direction and this capability is selectively controlled by an operator lever mounted on the motor housing itself.

The schematic of FIGURE 4 reflects the elements as they are disposed in FIGURE 1a, i.e., the spool 54 is not blocking passageway 53. When handle 58 is rotated approximately 45, the spool will assume the highspeed setting of FIGURE 1.

What has been set forth above is intended primarily as exemplary of a teaching of the invention to enable those skilled in the art in the practice thereof and it should, therefore, be understood that Within the scope of the appended claims the invention may be practiced in other ways than as specifically described.

What is new and desired to be protected by Letters Patent of the United States is 1. A fluid pressure energy translating device having, a housing, a rotatable cylinder barrel within said housing having a bearing surface at one end thereof and a plurality plurality of pistons in said chambers, a stationary camming surface angularly disposed to the axis of rotation of said barrel at the other end of said barrel against which the ends of said pistons are slidably engaged, means for maintaining said ends in engagement with said surface to cause riciprocation of said pistons in said chambers as they are rotated with said barrel wherein the improvement comprises: a valve assembly enclosing one end of said housing and having an inner surface in planar engagement with said bearing surface, said inner surface having rst, second and third port means formed therein sequentially communicating with said chambers through said openings as said barrel rotates, said valve assembly having an intake port for receiving a source of pressurized fluid and rst and second passageways communicating said port respectively with said first and second port means, a valve rotatably mounted in said assembly across said second passageway and having a portion for assuming blocking and non-blocking positions, an operator handle mounted on said assembly connected to said Valve for selectively moving said portion of said valve to either said blocking or said non-blocking position.

2. The device recited in claim 1 wherein said third port means includes two separate ports equivalent in length to said first and second ports.

3. The device recited in claim 2 wherein said valve includes a second portion for selectively blocking one of said two separate ports.

4. The device recited in claim 1 wherein said valve is cylindrical and has a groove formed therein which communicates first and second lengths of said second passageway when said valve is in said non-blocking position.

References Cited UNITED STATES PATENTS 1,763,474 6/1930 Mattern 91--283 2,253,617 8/1941 Griliith 91-283 3,232,056 2/1966 Heinrich et al 19?-162 PAUL E. MASLOUSKY, Primary Examiner.

U.S. Cl. X.R. 91-175, 176, 441, 449 

